1. Field of the Invention
The invention relates to a laser instrument with a laser light guiding device.
As regards style of construction, in the case of laser instruments one distinguishes between those wherein a laser outcoupling element extends in the longitudinal direction of a rod-shaped holding part and those in which the laser outcoupling element extends at right angles to the rod-shaped holding part.
The use of the laser instrument of the former type is restricted to applications in which the treatment point is surrounded by a large free space that is easily accessible, as is the case for example in the treatment with the laser instrument of the skin of the human body or the body of an animal. Such a laser instrument is described in DE 38 40 609 A1.
However, for ergonomic and visual reasons it is more advantageous to make use of a laser instrument having a laser outcoupling element extending at right angles to the rod-shaped holding part or handle part. Such a laser instrument can be comfortably held ergonomically with the operating hand, whereby the line of sight to the treatment point is improved, since it is directed at right angles to the center axis of the laser outcoupling element, or the laser instrument or the person conducting the treatment can carry out the work in such a position that the line of sight directed at right angles to the laser outcoupling element is favorable.
It becomes evident that not only the physical burden on the person conducting the treatment but also the quality of the work to be performed with the laser is dependent on a favorable structural shape of the laser instrument and also a favourable line of sight. In a favourable treatment position the person conducting the treatment can perform the work with reduced exertion and attentiveness, on the one hand more precisely and qualitatively better, and on the other hand for a longer time, since his/her physical powers are taxed to a lesser extent.
The aforementioned difficulties arise in particular at those treatment sites which are difficult to access, as is the case for example in body cavities and in particular in the oral cavity of the human body or the body of an animal. In such applications angular laser instruments are suitable--in effect, those structural types in which the laser outcoupling element is directed at right angles to the longitudinal center axis of the rod-shaped holding part or handle part. With such a laser instrument the emergent laser beam is directed transversely. By this means, on the one hand the access to various treatment sites in the body cavity is favorable, and on the other hand the laser instrument can both be held in ergonomically favorable manner and can be moved for the surgical operation and favorably observed. In this connection it should be taken into consideration that these activities have to be performed through the opening in the body cavity.
For the aforementioned reasons use is being made with increasing frequency of an aforementioned angular laser instrument for treatment both at treatment sites that are difficult to access and at easily accessible treatment sites. Although an angular laser instrument is more costly to produce, since it requires a deflection of the laser beams, the advantages described above outweigh this consideration.
In the following, a distinction has to be made between those laser instruments in which the laser outcoupling element is arranged in the holding part and those in which it protrudes from the holding part. With the former style of construction the laser radiation merely emerges from the holding part, in particular in focused form, towards a focal point or treatment point arranged at a certain spacing from the laser instrument. In the second case the laser radiation is also transmitted outside the holding part in the laser outcoupling element, whereby the outcoupling or the emergence of the laser beam takes place at the free end of the laser outcoupling element and whereby this free end can be brought right up to the tissue to be treated and, optionally, in addition to the irradiation a mechanical action can be exerted on the tissue with the laser outcoupling element.
2. Description of the Prior Art
A laser instrument of the type specified in the introduction is described in DE 40 30 734 A1 or in DE 40 38 809 C1.
The former printed publication presents a laser instrument which comprises on its front end a lateral angular extension, at the free end of which the laser radiation emerges in focused form through an exit aperture. With a view to deflecting the laser radiation, a mirror is provided in the angular region of the laser instrument. The laser outcoupling element is constituted by a lens which is arranged within the exit aperture in the laser instrument. Moreover, further optical elements for the purpose of guiding and transmitting the laser radiation in the laser instrument are provided.
In the second printed publication a dental laser instrument is described having a laser outcoupling element that protrudes laterally at the front end of a substantially straight holding part or handpiece and is held in the region of an exit aperture by means of a plug-in part. Within the handpiece a deflecting device for the laser beams is arranged upstream of the exit aperture, said deflecting device being constituted by a prism with an oblique refractive surface that faces away from the feed direction of the laser radiation. The surface of the prism that faces towards the laser radiation extends at a right angle to the feed direction of the laser radiation and parallel to the longitudinal center axis of the laser outcoupling element. At a distance from the prism in the rearward direction a lens is supported in the laser instrument or in the handle part so as to be axially displaceable, the purpose of which is to focus the laser radiation reaching the prism in such a way that use can be made of laser outcoupling elements of differing cross-sectional size--for example, a laser outcoupling element for an external dental treatment and a laser outcoupling element for a root-canal treatment.